New research reveals that single-use hot beverage cups can release thousands of microplastic particles into drinks, particularly when the liquid is hot. The study, published in the Journal of Hazardous Materials: Plastics, analysed 400 cups from Brisbane, Australia, including all-plastic cups and paper cups with a plastic lining.
Researchers found that heat is a primary driver of microplastic release. For all-plastic cups, switching from cold to hot water increased microplastic release by about 33%. A person drinking 300 millilitres of coffee daily from a polyethylene cup could ingest approximately 363,000 microplastic particles per year.
The study also compared materials: paper cups with plastic linings shed fewer microplastics than all-plastic cups at both 5°C and 60°C. High-resolution imaging showed that all-plastic cups have rougher inner surfaces, making it easier for particles to break away, especially when heat softens the plastic.
Globally, an estimated 500 billion single-use cups are used annually, with 1.45 billion in Australia alone. While the health impacts of microplastics are still being studied, the authors recommend using reusable cups made of stainless steel, ceramic, or glass for hot drinks. If disposable cups are necessary, plastic-lined paper cups are a better option than all-plastic ones.
